Flaga-Maryańczyk, Agnieszka, and Tomasz Stypka. “APPLICATION OF THE MODIFIED AHP METHOD AND ECO-LABELS FOR BIOMASS BOILER SELECTION FOR A SMALL HOTEL IN A MOUNTAIN REGION. A CASE STUDY”. Economics and Environment, vol. 59, no. 4, Oct. 2016, p. 15, https://ekonomiaisrodowisko.pl/journal/article/view/213.